Keychain helps you to manage SSH and GPG keys in a convenient and secure
manner. It acts as a frontend to ssh-agent and ssh-add, but allows you
to easily have one long running ssh-agent process per system, rather
than the norm of one ssh-agent per login session. Keychain also makes
it easy for remote cron jobs to securely "hook in" to a long-running
ssh-agent process, allowing your scripts to take advantage of key-based
logins.
